Approximately 2.8 million require mechanical ventilation in intensive care units (ICU) in the USA each year and, as a consequence, are unable to communicate using natural speech. The inability to speak can elicit feelings of distress, anger, fear, agitation and isolation. Preventable adverse events are more likely to occur among hospitalized patients who are older and those with communication difficulties. Since the majority of ICU days are devoted to the caring for older adults, critically ill older adults are particularly vulnerable. Critical care nurses are uniquely positioned to mitigate the detrimental effects of communication impairment during caring interactions with their older adult patients. Interaction behaviors, both positive and negative, used by the nurse can set the tone of the interaction. The goals of the proposed study are to: 1) measure and describe nurse and patient interaction behaviors and factors that may impact communication between nurses and nonspeaking critically ill older adults in the ICU and 2) explore the association between nurse and patient interaction behaviors and nursing care quality indicators. The specific aims are to: 1a) identify and describe interaction behaviors that nurses and nonspeaking critically ill older adults use during communication interactions in the ICU;1b) describe augmentative and alternative communication (AAC) use with critically ill older adults and descriptively compare the interaction behaviors with respect to AAC use;2) explore the association between interaction behaviors and nursing care quality indicators (sedation use and level, physical restraint use, pain management, and unplanned device disruption);3) psychometrically evaluate an interaction behavior instrument derived from prior observational research in ICU setting. The sample will include all adult patients >60 years of age (N=38) and their nurses (N=24) who participated in the Study of Patient-Nurse Effectiveness with Communication Strategies (SPEACS) (R01-HD043988). Interaction behaviors will be measured by rating videotaped interactions between nurses and patients. Patient clinical characteristics on quality indicators will be obtained from the existing SPEACS data set and medical chart review. Descriptive statistics will be used to describe the nurse and patient interaction behaviors and AAC use. Group comparative statistics will compare the differences between interaction behaviors with the use of AAC. The association between interaction behaviors and nursing care quality indicators will be explored through repeated measures analysis. Finally, reliability and validity of the instrument will be determined by inter and intra-rater agreement, factor analysis, and expert review. This study will provide a greater understanding of how interaction behaviors influence nursing care quality. In addition, this study will provide essential evidence needed to build the science on nurse sensitive quality and safety indicators in critical care. PUBLIC HEALTH RELEVANCE: Communication difficulties between nurses and mechanically ventilated older adults remain a significant problem in critical care. The purpose of this study is to improve the understanding of how augmentative and alternative communication (AAC) use is related to nurse and patient communication interaction behaviors. In addition, this study will provide novel evidence on the association between interaction behaviors and nursing care quality, which will contribute to the body of evidence on nurse sensitive quality and safety indicators in critical care.